Preparation method of heat insulation tile composite aerogel material

Abstract

The invention provides a preparation method of a heat insulation tile composite aerogel material, and belongs to the technical field of heat insulation tiles. The preparation method comprises the steps of silane-treated basalt fiber preparation, modified silicon carbide preparation and composite forming. The preparation method of the silane-treated basalt fiber comprises the following steps: putting basalt fiber into a pretreatment solution, preserving heat at 74-77 DEG C for 1.4-1.6 hours, putting the basalt fiber into an ammonium ceric nitrate solution, and impregnating at 56-60 DEG C for 36-45 minutes to obtain impregnated basalt fiber; putting the impregnated basalt fiber into an ethanol solution, adding gamma-mercaptopropyltrimethoxysilane, and stirring for 3.0-4.0 hours at the temperature of 70-75 DEG C, so as to obtain silane-treated basalt fiber; the heat insulation tile composite aerogel material prepared by adopting the preparation method disclosed by the invention is good in heat insulation performance and mechanical strength, good in high temperature resistance and excellent in stability performance in a complex environment.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal insulation tiles, and particularly relates to a method for preparing a composite aerogel material for thermal insulation tiles. Background Art

[0002] When a spacecraft enters the atmosphere of an extraterrestrial planet at high speed or re-enters the Earth's atmosphere from outer space, severe aerodynamic heating will occur due to its extremely high speed. It is very necessary to implement thermal protection measures on the surface of the spacecraft. The requirements of the aircraft for thermal insulation materials are relatively strict, which directly affects the safety and flight stability of the aircraft. It is very critical to add thermal insulation materials with heat insulation, high temperature resistance, wave transmission, and light weight to the surface of the aircraft to effectively prevent external heat from being transferred to the interior.

[0003] With the development of aerospace industry, thermal insulation tiles have gradually become a research hotspot for thermal insulation materials and thermal protection technologies in aircraft.

[0004] Thermal insulation tiles are a material with good temperature resistance, excellent thermal insulation performance and light weight. They can effectively block the transfer of heat, provide good thermal protection for aircraft in high temperature environments, and effectively improve the stability of the aircraft's external structure and the safety and stability of the operation of internal equipment; Thermal insulation tile composite aerogel material is a new type of material with excellent thermal insulation properties. It combines traditional thermal insulation tiles with nanoporous aerogel materials. In the aerospace field, it can be used on the surface of aircraft to resist the high temperature generated by friction in the atmosphere when returning to the earth. It has high application value and broad market prospects.

[0005] In the prior art, the preparation methods of thermal insulation tile composite aerogel materials generally include sol-gel in-situ molding method, impregnation-supercritical method and powder sintering composite method; The sol-gel in-situ forming method directly forms an aerogel layer on the surface of the insulation tile substrate to achieve a close bond between the aerogel and the insulation tile substrate. However, the thickness of the aerogel layer is difficult to control and is prone to cracking during the drying process, which reduces the product yield. The impregnation-supercritical method involves placing the insulating tile substrate in an aerogel precursor solution and obtaining a composite material through supercritical drying. This method can relatively completely maintain the nanoporous structure of the aerogel and enhance thermal insulation performance. However, the product suffers from insufficient interfacial bonding strength and high-temperature stability, a complex process, and high equipment requirements, which increases production costs and makes large-scale production difficult. The powder sintering composite method is to mix aerogel powder with insulation tile raw materials and then sinter them into shape. The process is simple and suitable for mass production, but the structure of the aerogel is easily destroyed during the sintering process, and the thermal insulation performance is greatly reduced.

[0006] It can be seen that the thermal insulation tile composite aerogel material prepared by the existing technology has the problem of low interface bonding strength, which will reduce the mechanical strength of the composite material, and also has the problem of poor high temperature stability and cannot be used in high temperature environment for a long time.

[0007] After searching, the researchers found that the thermal insulation tile composite aerogel material prepared by existing technology has certain high temperature resistance, but its application performance is poor in an environment with rapid changes in high and low temperatures, and it is easy to experience a sharp decline in performance.

[0008] Therefore, providing a preparation method for thermal insulation tile composite aerogel material to enhance the interface bonding strength, while improving the thermal insulation performance, mechanical properties, and high temperature resistance of the composite material, and ensuring the overall performance in a high and low temperature rapidly changing environment is a technical problem that needs to be solved urgently in the existing technology. Summary of the Invention

[0009] In order to solve the technical problems existing in the prior art, the present invention provides a method for preparing an insulating tile composite aerogel material. The insulating tile composite aerogel material has excellent thermal insulation performance and mechanical strength, good high temperature resistance, and excellent stability in complex environments.

[0010] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for preparing a composite aerogel material for thermal insulation tiles includes the steps of preparing silane-treated basalt fiber, preparing modified silicon carbide, and composite molding, as follows: 1. Preparation of Silane-treated Basalt Fiber The basalt fiber is placed in a pretreatment solution, the temperature is increased to 74-77° C., and the heat treatment is carried out for 1.4-1.6 hours. After the heat treatment, the fiber is washed and then placed in a cerium ammonium nitrate solution and immersed at 56-60° C. for 36-45 minutes. After the immersion is completed, the fiber is filtered, washed, and dried to obtain an impregnated basalt fiber. The impregnated basalt fiber is placed in an ethanol solution, γ-mercaptopropyltrimethoxysilane is added, the temperature is increased to 70-75° C., the fiber is stirred at this temperature for 3.0-4.0 hours, filtered, washed, and vacuum dried at 80-85° C. to a constant weight to obtain a silane-treated basalt fiber. The basalt fiber has a diameter of 110-130 nm and a length of 15-23 μm; The pretreatment solution is a mixture of ammonium fluoride solution, polyvinyl pyrrolidone and potassium perfluorooctane sulfonate, wherein the mass ratio of the ammonium fluoride solution, polyvinyl pyrrolidone and potassium perfluorooctane sulfonate is 50:0.7-0.9:0.4-0.6; the mass concentration of the ammonium fluoride solution is 4.8-5.2%; The mass ratio of the basalt fiber, the pretreatment solution, and the cerium ammonium nitrate solution is 10-14:100:95-105; The mass concentration of the ammonium cerium nitrate solution is 5.0-5.5%; The mass ratio of the impregnated basalt fiber, ethanol solution, and γ-mercaptopropyltrimethoxysilane is 9.6-10.3:100:1.0-1.4; The mass concentration of the ethanol solution is 26-30%.

[0011] 2. Preparation of modified silicon carbide The silicon carbide powder is placed in an oxygen flow for high-temperature treatment at a temperature of 410-430° C. for a time of 2.0-3.0 hours to obtain pretreated silicon carbide. The pretreated silicon carbide powder is placed in an ethanol solution, and an amino-modified chitosan solution is added at a rate of 0.8-1.2 g / min. After the addition is completed, the mixture is stirred at 34-36° C. for 48-52 minutes. After the stirring is completed, vinyltrimethoxysilane is added, the temperature is increased to 66-70° C., the mixture is stirred for 1.8-2.2 hours, and the mixture is filtered, washed, and dried to obtain modified silicon carbide. The oxygen flow is a mixed gas of ozone and oxygen, and the volume ratio of ozone to oxygen is 4-6:94-96; The mass ratio of the pretreated silicon carbide powder, ethanol solution, amino-modified chitosan solution, and vinyltrimethoxysilane is 7.2-7.6:78-83:42-46:0.80-0.85; The mass concentration of the ethanol solution is 20-25%; The amino-modified chitosan solution is a mixture of amino-modified chitosan and acetic acid solution, and the mass ratio of the amino-modified chitosan to the acetic acid solution is 3.3-3.7:100; The mass concentration of the acetic acid solution is 4.8-5.3%; The preparation method of the amino-modified chitosan comprises the following steps: adding chitosan to an acetic acid solution, stirring at room temperature for 2.0-2.5 hours, adding a 6.3-6.6 wt % sodium hydroxide solution to adjust the pH to 5.6-6.0, adding an amino-modifying liquid at a rate of 1.4-1.6 g / min, stirring at 38-42° C. for 57-65 minutes, adding a glutaraldehyde solution, raising the temperature to 52-57° C., and maintaining the temperature for reaction for 2.0-3.0 hours. After the reaction is complete, filtering, washing, and drying to obtain the amino-modified chitosan; The mass ratio of the chitosan, acetic acid solution, amino-modified liquid, and glutaraldehyde solution is 8.0-8.5:68-73:47-53:10-15; The mass concentration of the acetic acid solution is 4.0-4.5%; The mass concentration of the glutaraldehyde solution is 9.5-10.8%; The amino modification liquid is a mixture of spermine, hexamethylenediamine and deionized water, and the mass ratio of the spermine, hexamethylenediamine and deionized water is 1.0-1.5:2.1-2.6:100.

[0012] 3. Composite molding Modified silicon carbide was added to N,N-dimethylformamide, and after stirring evenly, silane-treated basalt fiber was added, and the temperature was increased to 60-65°C at a rate of 0.4-0.6°C / min, and the reaction was stirred for 3.0-3.5 hours. After the reaction was completed, the solid was filtered out, washed, dried to constant weight, and added to zirconium sol. Polyethyleneimine was added, and the temperature was increased to 60-64°C at a rate of 0.4-0.6°C / min. Ultrasonic treatment was performed, and the ultrasonic time was 2.3- 2.7h, ultrasonic power of 135-146W, ultrasonic frequency of 40-45kHz, after the ultrasonic treatment, pour into a mold for molding, and then freeze-dry, the drying time is 18-22h, the drying temperature is -47 ~ -42 ° C, after demolding, in an argon atmosphere, the temperature is increased to 806-814 ° C at a rate of 1.8-2.2 ° C / min, kept warm for 78-82 minutes, and naturally cooled to room temperature to obtain an insulating tile composite aerogel material; The mass ratio of the N,N-dimethylformamide, modified silicon carbide, silane-treated basalt fiber, zirconium sol, and polyethyleneimine is 200:9.2-9.6:2.4-2.8:115-124:0.8-1.2; The zirconium sol is prepared by adding zirconium oxychloride to a mixed solvent, stirring evenly, adding acetylacetone, stirring and reacting for 0.8-1.2 hours, then adding gadolinium oxide and yttrium oxide, stirring and reacting at 63-67° C. for 2.4-2.6 hours, then adding an ammonia solution to adjust the pH to 3.5-3.7, and keeping the temperature at 38-42° C. for 22-26 hours to obtain the zirconium sol; The mixed solvent is a mixture of anhydrous ethanol and deionized water, and the mass ratio of the anhydrous ethanol to the deionized water is 57-65:10; The mass ratio of the zirconium oxychloride, the mixed solvent, acetylacetone, gadolinium oxide, and yttrium oxide is 14.2-14.7:68-73:3.8-4.2:2.0-2.4:1.6-1.8; The mass concentration of the ammonia solution is 7.5-8.2%.

[0013] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. In the method for preparing the composite aerogel material for thermal insulation tiles, silicon carbide powder is used as the matrix and basalt fiber is used as the reinforcing skeleton, which can enhance the mechanical strength of the product. However, the bonding strength between basalt fiber and silicon carbide powder is poor. In the present invention, the basalt fiber is first treated with ammonium fluoride solution to etch the fiber surface, increase the roughness and active sites of the fiber surface, and combine with polyvinyl pyrrolidone and potassium perfluorooctane sulfonate to enhance the dispersibility and surface activity of the basalt fiber, promote the wetting performance of the pretreatment solution on the fiber, prevent the fiber from agglomerating, and promote the uniformity of etching. Then, the basalt fiber is treated with ammonium nitrate, which can decompose to generate Ce. 4+ , enhance the surface reaction activity, and then use a mercaptosilane coupling agent to treat the impregnated basalt fiber, thereby introducing mercapto groups on the surface of the basalt fiber, which can provide reaction sites with modified silicon carbide, improve the compatibility between the fiber and the matrix, and reduce interface defects; the present invention performs ozone high-temperature treatment on silicon carbide, which can generate a silicon dioxide layer on the surface of silicon carbide, increase the number of hydroxyl groups on the surface, and then introduce amino-modified chitosan. Amino-modified chitosan is prepared by modification with spermine and hexamethylenediamine, and more amino groups are introduced. Its long chain can enhance the flexibility of the molecular chain and the reaction sites, and is cross-linked by glutaraldehyde to obtain tri- The amino-modified chitosan with a three-dimensional network structure improves the dispersion performance of silicon carbide by coating the surface of silicon carbide with amino-modified chitosan. Then, the hydrolysis of the vinyl silane coupling agent and the condensation of the hydroxyl groups on the chitosan surface produce a modified silicon carbide with a stable cross-linked network. In the composite molding step, the silane-treated basalt fiber and the modified silicon carbide are chemically bonded to form an interpenetrating network, further enhancing the mechanical strength and high-temperature resistance of the product. Combined with the zirconium sol treatment, the zirconium sol penetrates into the network formed by the basalt fiber and silicon carbide, ensuring the thermal insulation performance of the product and making the product have excellent stability. 2. The thermal insulation tile composite aerogel material prepared by the preparation method of the present invention has a fracture toughness of 1.10-1.13 MPa·m 1 / 2 , compressive strength is 5.39-5.47MPa, compressive strength is 6.07-6.18MPa, thermal conductivity is 0.036-0.039W / (m·K); 3. The thermal insulation tile composite aerogel material prepared by the preparation method of the present invention was kept at 1200°C for 12 hours, and the fracture toughness was measured again to be 1.05-1.09 MPa·m 1 / 2 , compressive strength is 5.10-5.22MPa, and compression strength is 5.77-5.91MPa; 4. The thermal insulation tile composite aerogel material prepared by the preparation method of the present invention was heated to 1200°C at a rate of 30°C / min, kept warm for 30 minutes, and then cooled to 26°C at a rate of 50°C / min. The above operation constituted one treatment cycle. After 20 treatment cycles, the fracture toughness was measured again to be 1.00-1.04 MPa·m 1 / 2 , the compressive strength is 4.86-4.98MPa, and the compression strength is 5.48-5.65MPa. DETAILED DESCRIPTION

[0014] In order to more clearly understand the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described.

[0015] Example 1 1. Preparation of Silane-treated Basalt Fiber 12 g of basalt fiber was placed in 100 g of pretreatment solution, the temperature was increased to 76° C., and the solution was kept warm for 1.5 h. After the heat treatment, the solution was washed and then placed in 100 g of 5.2 wt% cerium ammonium nitrate solution and immersed at 58° C. for 40 min. After the immersion, the solution was filtered, washed, and dried to obtain impregnated basalt fiber. 10 g of impregnated basalt fiber was placed in 100 g of 28 wt% ethanol solution, 1.2 g of γ-mercaptopropyltrimethoxysilane was added, the temperature was increased to 73° C., the solution was kept warm and stirred for 3.5 h, filtered, washed, and vacuum dried at 82° C. to constant weight to obtain silane-treated basalt fiber. The basalt fiber has a diameter of 120 nm and a length of 20 μm; The pretreatment solution is a mixture of ammonium fluoride solution, polyvinyl pyrrolidone and potassium perfluorooctane sulfonate, wherein the mass ratio of the ammonium fluoride solution, polyvinyl pyrrolidone and potassium perfluorooctane sulfonate is 50:0.8:0.5; the mass concentration of the ammonium fluoride solution is 5.0%; 2. Preparation of modified silicon carbide Silicon carbide powder was placed in an oxygen flow for high-temperature treatment at 420°C for 2.5 hours to obtain pretreated silicon carbide. 7.4 g of the pretreated silicon carbide powder was placed in 80 g of a 23 wt% ethanol solution, and 44 g of an amino-modified chitosan solution was added at a rate of 1.0 g / min. After the addition was completed, the mixture was stirred at 35°C for 50 minutes. After the stirring was completed, 0.82 g of vinyltrimethoxysilane was added, the temperature was raised to 68°C, and the mixture was stirred for 2.0 hours. The mixture was filtered, washed, and dried to obtain modified silicon carbide. The oxygen flow is a mixed gas of ozone and oxygen, and the volume ratio of ozone to oxygen is 5:95; The amino-modified chitosan solution is a mixture of amino-modified chitosan and 5.0 wt % acetic acid solution, and the mass ratio of the amino-modified chitosan to the 5.0 wt % acetic acid solution is 3.5:100; The preparation method of the amino-modified chitosan comprises the following steps: adding 8.2 g of chitosan to 70 g of a 4.2 wt% acetic acid solution, stirring at room temperature for 2.3 h, adding a 6.5 wt% sodium hydroxide solution to adjust the pH to 5.8, adding 50 g of an amino-modified liquid at a rate of 1.5 g / min, stirring at 40° C. for 60 min, adding 12 g of a 10 wt% glutaraldehyde solution, raising the temperature to 54° C., and keeping the temperature for reaction for 2.5 h. After the reaction is complete, filtering, washing, and drying the mixture to obtain the amino-modified chitosan; The amino modification liquid is a mixture of spermine, hexamethylenediamine and deionized water, and the mass ratio of the spermine, hexamethylenediamine and deionized water is 1.2:2.3:100.

[0016] 3. Composite molding 9.4 g of modified silicon carbide was added to 200 g of N, N-dimethylformamide, and after stirring evenly, 2.6 g of silane-treated basalt fiber was added, the temperature was increased to 62 ° C at a rate of 0.5 ° C / min, and the reaction was stirred for 3.3 hours. After the reaction, the solid was filtered out, washed and dried to constant weight, and then added to 120 g of zirconium sol. 1.0 g of polyethyleneimine was added, and the temperature was increased to 62 ° C at a rate of 0.5 ° C / min. Ultrasonic treatment was performed for 2.5 hours, the ultrasonic power was 140 W, and the ultrasonic frequency was 43 kHz. After the ultrasonic treatment, it was poured into a mold for molding, and then freeze-dried for 20 hours at a drying temperature of -45 ° C. After demolding, the temperature was increased to 810 ° C at a rate of 2.0 ° C / min in an argon atmosphere, kept warm for 80 minutes, and naturally cooled to room temperature to obtain an insulating tile composite aerogel material; The zirconium sol is prepared by adding 14.5 g of zirconium oxychloride to 70 g of a mixed solvent, stirring evenly, adding 4.0 g of acetylacetone, stirring and reacting for 1.0 h, then adding 2.2 g of gadolinium oxide and 1.7 g of yttrium oxide, stirring and reacting at 65° C. for 2.5 h, then adding 8.0 wt % ammonia solution to adjust the pH to 3.6, and keeping the mixture at 40° C. for 24 h to obtain the zirconium sol; The mixed solvent is a mixture of anhydrous ethanol and deionized water, and the mass ratio of the anhydrous ethanol to the deionized water is 60:10.

[0017] Example 2 1. Preparation of Silane-treated Basalt Fiber 10 g of basalt fiber was placed in 100 g of pretreatment solution, the temperature was increased to 74° C., and the solution was kept warm for 1.4 h. After the insulation treatment, the solution was washed and then placed in 95 g of 5.0 wt% cerium ammonium nitrate solution and immersed at 56° C. for 36 min. After the immersion, the solution was filtered, washed, and dried to obtain impregnated basalt fiber. 9.6 g of the impregnated basalt fiber was placed in 100 g of 26 wt% ethanol solution, 1.0 g of γ-mercaptopropyltrimethoxysilane was added, the temperature was increased to 70° C., the solution was kept warm and stirred for 3.0 h, filtered, washed, and vacuum dried at 80° C. to constant weight to obtain silane-treated basalt fiber. The basalt fiber has a diameter of 110 nm and a length of 23 μm; The pretreatment solution is a mixture of ammonium fluoride solution, polyvinyl pyrrolidone and potassium perfluorooctane sulfonate, wherein the mass ratio of the ammonium fluoride solution, polyvinyl pyrrolidone and potassium perfluorooctane sulfonate is 50:0.7:0.4; the mass concentration of the ammonium fluoride solution is 4.8%; 2. Preparation of modified silicon carbide Silicon carbide powder was placed in an oxygen flow for high-temperature treatment at 410°C for 3.0 hours to obtain pretreated silicon carbide. 7.2 g of the pretreated silicon carbide powder was placed in 78 g of a 20 wt% ethanol solution, and 42 g of an amino-modified chitosan solution was added at a rate of 0.8 g / min. After the addition was completed, the mixture was stirred at 34°C for 48 minutes. After the stirring was completed, 0.80 g of vinyltrimethoxysilane was added, the temperature was raised to 66°C, and the mixture was stirred for 1.8 hours. The mixture was filtered, washed, and dried to obtain modified silicon carbide. The oxygen flow is a mixed gas of ozone and oxygen, and the volume ratio of ozone to oxygen is 4:96; The amino-modified chitosan solution is a mixture of amino-modified chitosan and 4.8 wt % acetic acid solution, and the mass ratio of the amino-modified chitosan to the 4.8 wt % acetic acid solution is 3.3:100; The preparation method of the amino-modified chitosan comprises the following steps: adding 8.0 g of chitosan to 68 g of a 4.0 wt% acetic acid solution, stirring at room temperature for 2.0 h, adding a 6.3 wt% sodium hydroxide solution to adjust the pH to 5.6, adding 47 g of an amino-modified liquid at a rate of 1.4 g / min, stirring at 38° C. for 65 min, adding 10 g of a 10.8 wt% glutaraldehyde solution after the addition is completed, raising the temperature to 52° C., and keeping the temperature for reaction for 3.0 h. After the reaction is completed, filtering, washing, and drying the mixture to obtain the amino-modified chitosan; The amino modification liquid is a mixture of spermine, hexamethylenediamine and deionized water, and the mass ratio of the spermine, hexamethylenediamine and deionized water is 1.0:2.1:100.

[0018] 3. Composite molding 9.2 g of modified silicon carbide was added to 200 g of N, N-dimethylformamide, and after stirring evenly, 2.4 g of silane-treated basalt fiber was added, the temperature was increased to 60 ° C at a rate of 0.4 ° C / min, and the reaction was stirred for 3.0 h. After the reaction, the solid was filtered out, washed and dried to constant weight, and then added to 115 g of zirconium sol. 0.8 g of polyethyleneimine was added, and the temperature was increased to 60 ° C at a rate of 0.4 ° C / min. Ultrasonic treatment was performed, the ultrasonic time was 2.3 h, the ultrasonic power was 135 W, and the ultrasonic frequency was 40 kHz. After the ultrasonic treatment, it was poured into a mold for molding, and then freeze-dried for 22 h and at a drying temperature of -42 ° C. After demolding, the temperature was increased to 806 ° C at a rate of 1.8 ° C / min in an argon atmosphere, kept warm for 78 min, and naturally cooled to room temperature to obtain an insulating tile composite aerogel material; The zirconium sol is prepared by adding 14.2 g of zirconium oxychloride to 68 g of a mixed solvent, stirring evenly, adding 3.8 g of acetylacetone, stirring and reacting for 0.8 h, then adding 2.0 g of gadolinium oxide and 1.6 g of yttrium oxide, stirring and reacting at 63° C. for 2.4 h, then adding 7.5 wt % ammonia solution to adjust the pH to 3.5, and keeping the mixture at 38° C. for 26 h to obtain the zirconium sol; The mixed solvent is a mixture of anhydrous ethanol and deionized water, and the mass ratio of the anhydrous ethanol to the deionized water is 65:10.

[0019] Example 3 1. Preparation of Silane-treated Basalt Fiber 14 g of basalt fiber was placed in 100 g of a pretreatment solution, the temperature was raised to 77° C., and the solution was kept warm for 1.6 h. After the insulation treatment, the solution was washed and then placed in 105 g of a 5.5 wt% cerium ammonium nitrate solution and immersed at 60° C. for 45 min. After the immersion, the solution was filtered, washed, and dried to obtain an impregnated basalt fiber. 10.3 g of the impregnated basalt fiber was placed in 100 g of a 30 wt% ethanol solution, 1.4 g of γ-mercaptopropyltrimethoxysilane was added, the temperature was raised to 75° C., the solution was kept warm and stirred for 4.0 h, filtered, washed, and vacuum dried at 85° C. to constant weight to obtain a silane-treated basalt fiber. The basalt fiber has a diameter of 130 nm and a length of 15 μm; The pretreatment solution is a mixture of ammonium fluoride solution, polyvinyl pyrrolidone and potassium perfluorooctane sulfonate, wherein the mass ratio of the ammonium fluoride solution, polyvinyl pyrrolidone and potassium perfluorooctane sulfonate is 50:0.9:0.6; the mass concentration of the ammonium fluoride solution is 5.2%; 2. Preparation of modified silicon carbide Silicon carbide powder was placed in an oxygen flow for high-temperature treatment at 430°C for 2.0 hours to obtain pretreated silicon carbide. 7.6 g of the pretreated silicon carbide powder was placed in 83 g of a 25 wt% ethanol solution, and 46 g of an amino-modified chitosan solution was added at a rate of 1.2 g / min. After the addition was completed, the mixture was stirred at 36°C for 52 minutes. After the stirring was completed, 0.85 g of vinyltrimethoxysilane was added, the temperature was raised to 70°C, and the mixture was stirred for 2.2 hours. The mixture was filtered, washed, and dried to obtain modified silicon carbide. The oxygen flow is a mixed gas of ozone and oxygen, and the volume ratio of ozone to oxygen is 6:94; The amino-modified chitosan solution is a mixture of amino-modified chitosan and 5.3 wt % acetic acid solution, and the mass ratio of the amino-modified chitosan to the 5.3 wt % acetic acid solution is 3.7:100; The preparation method of the amino-modified chitosan comprises the following steps: adding 8.5 g of chitosan to 73 g of a 4.5 wt % acetic acid solution, stirring at room temperature for 2.5 h, adding a 6.6 wt % sodium hydroxide solution to adjust the pH to 6.0, adding 53 g of an amino-modified liquid at a rate of 1.6 g / min, stirring at 42° C. for 57 min, adding 15 g of a 9.5 wt % glutaraldehyde solution after the addition is completed, raising the temperature to 57° C., and keeping the temperature for reaction for 2.0 h. After the reaction is completed, filtering, washing, and drying the mixture to obtain the amino-modified chitosan; The amino modification liquid is a mixture of spermine, hexamethylenediamine and deionized water, and the mass ratio of the spermine, hexamethylenediamine and deionized water is 1.5:2.6:100.

[0020] 3. Composite molding 9.6 g of modified silicon carbide was added to 200 g of N, N-dimethylformamide, and after stirring evenly, 2.8 g of silane-treated basalt fiber was added, the temperature was increased to 65 ° C at a rate of 0.6 ° C / min, and the reaction was stirred for 3.5 hours. After the reaction, the solid was filtered out, washed and dried to constant weight, and then added to 124 g of zirconium sol. 1.2 g of polyethyleneimine was added, and the temperature was increased to 64 ° C at a rate of 0.6 ° C / min. Ultrasonic treatment was performed, the ultrasonic time was 2.7 h, the ultrasonic power was 146 W, and the ultrasonic frequency was 45 kHz. After the ultrasonic treatment, it was poured into a mold for molding, and then freeze-dried for 18 hours and at a drying temperature of -47 ° C. After demolding, the temperature was increased to 814 ° C at a rate of 2.2 ° C / min in an argon atmosphere, kept warm for 82 minutes, and naturally cooled to room temperature to obtain an insulating tile composite aerogel material; The zirconium sol is prepared by adding 14.7 g of zirconium oxychloride to 73 g of a mixed solvent, stirring evenly, adding 4.2 g of acetylacetone, stirring and reacting for 1.2 hours, then adding 2.4 g of gadolinium oxide and 1.8 g of yttrium oxide, stirring and reacting at 67° C. for 2.6 hours, then adding 8.2 wt % ammonia solution to adjust the pH to 3.7, and keeping the mixture at 42° C. for 22 hours to obtain the zirconium sol; The mixed solvent is a mixture of anhydrous ethanol and deionized water, and the mass ratio of the anhydrous ethanol to the deionized water is 57:10.

[0021] In the method for preparing the composite aerogel material for thermal insulation tiles, silicon carbide powder is used as the matrix and basalt fiber is used as the reinforcing skeleton, which can enhance the mechanical strength of the product. The bonding strength between basalt fiber and silicon carbide powder is poor. The present invention first uses ammonium fluoride solution to treat the basalt fiber to etch the fiber surface, increase the roughness and active sites of the fiber surface, and combines polyvinyl pyrrolidone and potassium perfluorooctane sulfonate to enhance the dispersibility and surface activity of the basalt fiber, promote the wetting performance of the pretreatment solution on the fiber, prevent the fiber from agglomerating, and promote the uniformity of etching. Then, ammonium cerium nitrate is used for treatment, which can decompose to generate Ce. 4+ , enhance the surface reaction activity, and then use a mercaptosilane coupling agent to treat the impregnated basalt fiber, thereby introducing mercapto groups on the surface of the basalt fiber, which can provide reaction sites with modified silicon carbide, improve the compatibility between the fiber and the matrix, and reduce interface defects; the present invention performs ozone high-temperature treatment on silicon carbide, which can generate a silicon dioxide layer on the surface of silicon carbide, increase the number of hydroxyl groups on the surface, and then introduce amino-modified chitosan. Amino-modified chitosan is prepared by modification with spermine and hexamethylenediamine, and more amino groups are introduced. Its long chain can enhance the flexibility of the molecular chain and the reaction sites, and is cross-linked by glutaraldehyde to obtain tri- The amino-modified chitosan with a three-dimensional network structure improves the dispersion performance of silicon carbide by coating the surface of silicon carbide with amino-modified chitosan, and then obtains a modified silicon carbide with a stable cross-linked network through the hydrolysis of the vinyl silane coupling agent and condensation with the hydroxyl groups on the surface of chitosan; in the composite molding step, the silane-treated basalt fiber and the modified silicon carbide are combined through chemical bonds to obtain an interpenetrating network, which further enhances the mechanical strength and high-temperature resistance of the product. Combined with the zirconium sol treatment, the zirconium sol penetrates into the network of basalt fiber and silicon carbide, ensuring the thermal insulation performance of the product and making the product have excellent stability.

[0022] Comparative Example 1 The technical solution of Example 1 was adopted, except that: the step of preparing silane-treated basalt fibers was omitted; in the composite molding step, an equal amount of untreated basalt fibers was used to replace the silane-treated basalt fibers, wherein the diameter of the basalt fibers was 120 nm and the length was 20 μm; Comparative Example 1 directly uses untreated basalt fiber to replace the silane-treated basalt fiber, which omits the silane treatment step for the basalt fiber. The basalt fiber is highly inert, and there is only a weak physical adsorption effect between it and the silicon carbide matrix. The interface bonding is poor, and interface defects are easily formed, which leads to reduced crack propagation resistance, easy cracking of the product, and reduced fracture toughness and strength performance. In addition, the unevenly dispersed basalt fiber will cause the heat conduction path to be interrupted, thereby increasing the thermal conductivity and reducing the thermal insulation performance. In addition, the product has poor high temperature resistance and stability, which limits the application of the product.

[0023] Comparative Example 2 The technical solution of Example 1 is adopted, except that: (1) The step of preparing modified silicon carbide is to place silicon carbide powder in an oxygen flow for high-temperature treatment at a temperature of 420°C for a treatment time of 2.5 hours, and obtain modified silicon carbide after the treatment is completed; the oxygen flow is a mixed gas of ozone and oxygen, and the volume ratio of ozone to oxygen is 5:95; (2) In the preparation method of zirconium sol in the composite molding step, the operation of "then adding 2.2 g of gadolinium oxide and 1.7 g of yttrium oxide, and stirring the reaction at 65°C for 2.5 hours" is omitted.

[0024] Comparative Example 2 only uses ozone-oxygen treatment on silicon carbide, and does not introduce amino-modified chitosan and vinyl silane coupling agent, which will result in fewer active sites on the surface of silicon carbide and weak bonding with the fiber, thereby reducing the strength and toughness of the product. Comparative Example 2 also omits the addition of gadolinium oxide and yttrium oxide, which will reduce the high temperature resistance and stability of the product. It will also densify the sintering process and make the pore structure of the zirconium sol uneven, resulting in higher thermal conductivity and poorer thermal insulation performance.

[0025] Performance Testing The fracture toughness, compressive strength, compression strength, thermal conductivity, high temperature resistance and stability of the thermal insulation tile composite aerogel materials prepared by the preparation methods of Examples 1-3 and Comparative Examples 1-2 were tested respectively, as follows:

[0026] Among them, the high temperature resistance is to keep the thermal insulation tile composite aerogel material prepared by the preparation method of Examples 1-3 and Comparative Examples 1-2 at 1200°C for 12 hours, and then test the fracture toughness, compressive strength and compression strength of the product; The stability performance is achieved by raising the temperature of the thermal insulation tile composite aerogel material obtained by the preparation method of Examples 1-3 and Comparative Examples 1-2 to 1200°C at a rate of 30°C / min, keeping the temperature for 30 minutes, and then lowering the temperature to 26°C at a rate of 50°C / min. The above operation is regarded as one treatment cycle. 20 treatment cycles are performed continuously, and the fracture toughness, compressive strength, and compressive strength of the product are tested again.

[0027] Unless otherwise specified, all percentages used in the present invention are by mass.

[0028] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a composite aerogel material for thermal insulation tiles, characterized in that: The method includes the steps of preparing silane-treated basalt fiber, preparing modified silicon carbide, and composite molding; The steps of preparing the silane-treated basalt fiber are as follows: placing the basalt fiber in a pretreatment solution, keeping the temperature at 74-77° C. for 1.4-1.6 hours, placing the basalt fiber in a cerium ammonium nitrate solution, and soaking it at 56-60° C. for 36-45 minutes to obtain the impregnated basalt fiber; placing the impregnated basalt fiber in an ethanol solution, adding γ-mercaptopropyltrimethoxysilane, and stirring at 70-75° C. for 3.0-4.0 hours to obtain the silane-treated basalt fiber; The pretreatment solution is a mixture of ammonium fluoride solution, polyvinyl pyrrolidone and potassium perfluorooctane sulfonate; The modified silicon carbide is prepared by placing pretreated silicon carbide powder in an ethanol solution, adding an amino-modified chitosan solution, stirring at 34-36° C. for 48-52 minutes, adding vinyltrimethoxysilane, and reacting at 66-70° C. for 1.8-2.2 hours to obtain the modified silicon carbide; The amino-modified chitosan solution is a mixture of amino-modified chitosan and acetic acid solution. The preparation method of the amino-modified chitosan comprises the following steps: adding chitosan to acetic acid solution, stirring for 2.0-2.5 hours, adding sodium hydroxide solution to adjust the pH to 5.6-6.0, adding amino-modified liquid, stirring at 38-42° C. for 57-65 minutes, adding glutaraldehyde solution, reacting at 52-57° C. for 2.0-3.0 hours, and obtaining amino-modified chitosan.

2. The method for preparing a thermal insulation tile composite aerogel material according to claim 1, characterized in that: In the step of preparing the silane-treated basalt fiber, the basalt fiber has a diameter of 110-130 nm and a length of 15-23 μm; The mass ratio of the basalt fiber, the pretreatment solution, and the cerium ammonium nitrate solution is 10-14:100:95-105; The mass concentration of the ammonium cerium nitrate solution is 5.0-5.5%; The mass ratio of the impregnated basalt fiber, ethanol solution, and γ-mercaptopropyltrimethoxysilane is 9.6-10.3:100:1.0-1.4; The mass concentration of the ethanol solution is 26-30%.

3. The method for preparing a thermal insulation tile composite aerogel material according to claim 1, characterized in that: In the pretreatment solution, the mass ratio of the ammonium fluoride solution, polyvinyl pyrrolidone and potassium perfluorooctane sulfonate is 50:0.7-0.9:0.4-0.6; and the mass concentration of the ammonium fluoride solution is 4.8-5.2%.

4. The method for preparing a thermal insulation tile composite aerogel material according to claim 1, characterized in that: In the step of preparing modified silicon carbide, the method for preparing the pretreated silicon carbide is to place silicon carbide powder in an oxygen flow for high-temperature treatment at a temperature of 410-430° C. for a treatment time of 2.0-3.0 hours, and obtain pretreated silicon carbide after the treatment is completed; The oxygen flow is a mixed gas of ozone and oxygen, and the volume ratio of ozone to oxygen is 4-6:94-96.

5. The method for preparing a thermal insulation tile composite aerogel material according to claim 1, characterized in that: In the step of preparing modified silicon carbide, the mass ratio of the pretreated silicon carbide powder, ethanol solution, amino-modified chitosan solution, and vinyltrimethoxysilane is 7.2-7.6:78-83:42-46:0.80-0.85; The mass concentration of the ethanol solution is 20-25%; In the amino-modified chitosan solution, the mass ratio of the amino-modified chitosan to the acetic acid solution is 3.3-3.7:100; The mass concentration of the acetic acid solution is 4.8-5.3%.

6. The method for preparing a composite aerogel material for thermal insulation tiles according to claim 1, characterized in that: In the preparation method of the amino-modified chitosan, the mass ratio of the chitosan, acetic acid solution, amino-modified liquid, and glutaraldehyde solution is 8.0-8.5:68-73:47-53:10-15; The mass concentration of the acetic acid solution is 4.0-4.5%; The mass concentration of the glutaraldehyde solution is 9.5-10.8%; The amino modification liquid is a mixture of spermine, hexamethylenediamine and deionized water, and the mass ratio of the spermine, hexamethylenediamine and deionized water is 1.0-1.5:2.1-2.6:

100.

7. The method for preparing a composite aerogel material for thermal insulation tiles according to claim 1, characterized in that: The composite molding step comprises adding modified silicon carbide to N,N-dimethylformamide, stirring evenly, adding silane-treated basalt fiber, raising the temperature to 60-65°C at a rate of 0.4-0.6°C / min, stirring and reacting for 3.0-3.5 hours, filtering out solid matter after the reaction, washing and drying to constant weight, adding solid matter to zirconium sol, adding polyethyleneimine, raising the temperature to 60-64°C at a rate of 0.4-0.6°C / min, and performing ultrasonic treatment for a period of time. The ultrasonic treatment is carried out for 2.3-2.7 hours, the ultrasonic power is 135-146W, the ultrasonic frequency is 40-45kHz, and after the ultrasonic treatment, it is poured into a mold for molding, and then freeze-dried. The drying time is 18-22 hours, and the drying temperature is -47 to -42°C. After demolding, the temperature is increased to 806-814°C at a rate of 1.8-2.2°C / min in an argon atmosphere, and kept warm for 78-82 minutes. After naturally cooling to room temperature, the thermal insulation tile composite aerogel material is obtained.

8. The method for preparing a composite aerogel material for thermal insulation tiles according to claim 7, characterized in that: The mass ratio of the N,N-dimethylformamide, modified silicon carbide, silane-treated basalt fiber, zirconium sol, and polyethyleneimine is 200:9.2-9.6:2.4-2.8:115-124:0.8-1.

2.

9. The method for preparing a composite aerogel material for thermal insulation tiles according to claim 8, characterized in that: The zirconium sol is prepared by adding zirconium oxychloride to a mixed solvent, stirring evenly, adding acetylacetone, stirring and reacting for 0.8-1.2 hours, then adding gadolinium oxide and yttrium oxide, stirring and reacting at 63-67° C. for 2.4-2.6 hours, then adding an ammonia solution to adjust the pH to 3.5-3.7, and keeping the temperature at 38-42° C. for 22-26 hours to obtain the zirconium sol; The mixed solvent is a mixture of anhydrous ethanol and deionized water, and the mass ratio of the anhydrous ethanol to the deionized water is 57-65:10; The mass ratio of the zirconium oxychloride, the mixed solvent, acetylacetone, gadolinium oxide, and yttrium oxide is 14.2-14.7:68-73:3.8-4.2:2.0-2.4:1.6-1.8; The mass concentration of the ammonia solution is 7.5-8.2%.

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